EP0414678B1 - Höhenregelungssystem für ein fahrzeug mit luftfederung - Google Patents
Höhenregelungssystem für ein fahrzeug mit luftfederung Download PDFInfo
- Publication number
- EP0414678B1 EP0414678B1 EP19880903239 EP88903239A EP0414678B1 EP 0414678 B1 EP0414678 B1 EP 0414678B1 EP 19880903239 EP19880903239 EP 19880903239 EP 88903239 A EP88903239 A EP 88903239A EP 0414678 B1 EP0414678 B1 EP 0414678B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- height
- adjustment system
- height adjustment
- characteristic curve
- vehicle body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
- B60G17/0152—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit
- B60G17/0155—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit pneumatic unit
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S280/00—Land vehicles
- Y10S280/01—Load responsive, leveling of vehicle
Definitions
- the present invention relates to a height adjustment system of the kind described in the pre-characterising clause of claim 1.
- a height adjustment system of the kind described in the pre-characterising clause of claim 1.
- Such a system is known from EP-A-0091017 wherein compressed air is admitted to the air spring when a distance sensor senses that the height of the vehicle body is below a lower threshold and air is released from the air spring when the distance sensor senses that the body height is above an upper threshold.
- the adjustment travel extends beyond that at closure of the solenoid valve arrangement.
- An attempt to compensate for this overshoot is made by appropriate choice of the upper and lower thresholds. However, this does not take into account the fact that the amount of overshoot depends also on the velocity of vertical movement of the vehicle body relative to the axle at the instant of closure of the valve arrangement and possibly other factors.
- the invention is readily realized by the use of a characteristic curve stored in a memory in accordance with claim 2. Sufficient accuracy can be obtained by adopting the measures of claims 3 and 4.
- the characteristic curve can be determined empirically or by trial and error in accordance with claim 5 or 6.
- the stored characteristic can be corrected or a choice out of a range of stored characteristics can be made, in accordance with claim 7. This has the advantage that compensation can be made for changes which occur in the friction and damping characteristics while the vehicle is in use.
- Fig. 1 shows diagrammatically a part of a vehicle body 10 attached to an axle 12 by an air suspension 14.
- the air suspension 14 comprises an air spring bellows 16, an oscillation damper 18 and a height measuring sensor 20, each arranged between the vehicle body 10 and the axle 12.
- the height measuring sensor 20 can be a simple potentiometer or variable resistor.
- the air spring bellows 16 is filled and emptied as required by a compressed air reservoir 22 and a solenoid valve arrangement 24.
- the reservoir 22 is charged from a compressor (not shown) via a line 26 containing a non-return valve 28.
- the valve arrangement 24 comprises a 3-port, 2-position valve 30 and a 2-port, 2-position valve 32 in a line 34 between the reservoir 22 and the suspension bellows 16.
- valves are spring-biased to their positions shown and are operated by solenoids 36, 38 with the assistance of air pressure from the reservoir 22.
- solenoids 36, 38 With the assistance of air pressure from the reservoir 22.
- the valve arrangement 24 cannot be opened.
- Actuation of both valves 30, 32 connects the air spring bellows 16 to the reservoir 22 in order to feed compressed air to the air suspension 14 and thereby increase the height h of the vehicle body 10 relative to the axle 12.
- Actuation of the valve 32 alone connects the air spring bellows 16 via the unactuated valve 30 to exhaust and thereby decrease the height h of the vehicle body 10.
- the height sensor 20 is connected to a comparator 40 for raising the vehicle body and to a comparator 42 for lowering the body.
- the outputs of the comparators 40, 42 are connected to a control computer 44 which energises the valve solenoids 36, 38 via end stage amplifiers 46, 48; respectively.
- the output h of the height sensor 20 is differentiated in a differentiator 50 to obtain the velocity ⁇ of vertical movement of the vehicle body and this velocity ⁇ is fed to a memory zone 52 (which may be part of the computer 44) in which is stored a characteristic curve.
- This characteristic curve which is shown in Fig. 3, gives the amount ⁇ by which the switching thresholds for the comparators 40 and 42 must be adjusted to compensate for the frictional forces in the oscillation damper 18.
- the required threshold adjustment ⁇ is directly proportional to the velocity of vertical movement of the vehicle body so that the majority of the characteristic curve is represented by a straight line of suitable slope.
- ⁇ min at velocities below V min which is determined by the expected errors of measurement and calculation.
- ⁇ max at velocities above V max which is determined by the air pressure in the reservoir 22, the capacity of the air spring bellows 16 and the flow cross sections of the valves 30, 32 and the air line 34.
- a subtractor 54 the height adjustment ⁇ is subtracted from a height value h 1 which it is desired to obtain when increasing the body height h from a too low a value.
- the height adjustment ⁇ is added to a height value h 2 which it is desired to obtain when the body height h is decreasing from a too high a value.
- the outputs of the subtractor 54 and the adder 56 are applied to the reference inputs of the comparators 40 and 42, respectively.
- h 1 should equal h 2 but, in practice, it is necessary to build some hysteresis into the system to avoid an excessive number of readjustment operations. Nevertheless, it is possible to feed the same desired height value h o to both the subtractor 54 and the adder 56 if the minimum threshold adjustment ⁇ min is increased to establish the hysteresis.
- the comparator 40 supplies a signal to the computer 44 which energises both valve solenoids 36, 38, whereby to admit compressed air to the air spring bellows 16.
- the velocity ⁇ of the consequent height adjustment is fed to the memory zone 52 which delivers a threshold adjustment ⁇ determined by the stored characteristic curve.
- the switching off threshold of the comparator 44 is thus adjusted to h 1- ⁇ , whereby the computer 44 closes the valves 30, 32 before the desired body height h 1 (or h o ) is reached.
- the stored characteristic curve is so chosen that the body reaches the desired height h 1 (or h o ) when the frictional forces in the damper 18 have dissipated.
- the comparator 42 signals the comparator 44 to energise only the solenoid 38 of the valve 32, whereby to discharge air from the air spring bellows 16.
- the valve 32 is closed when the height h reaches the switching off threshold h 2 + ⁇ to establish the desired body height h 2 (or h o ) when the frictional forces have dissipated.
- V min 5 mm / sec
- V max 50 mm / sec.
- the height adjustment falls short of the desired value in the case of low adjustment velocities and overshoots the desired value in the event of high adjustment velocities.
- the actual adjustment may depart by ⁇ 15 mm from the desired value.
- this departure can be reduced to ⁇ 2 mm when the vehicle is stationary. Due to vehicle oscillations when the vehicle is moving, the deviation from the desired value is increased both with and without the invention, in spite of filtering of the measured height signals from the sensor.
- the characteristic curve of Fig. 3 can be established empirically by making measurements of the actual adjustment velocity ⁇ and the consequent value of the eventual overshoot when the frictional forces have been overcome or dissipated. Another way is by trial and error. An initial characteristic curve is established arbitrarily and the error in the eventual height adjustment actually produced by the system is noted. The characteristic curve stored in the memory zone is then changed in a sense to reduce this error. The process is then repeated as often as is necessary to bring this error down to an acceptable value. In the trial and error method, the corrected characteristic curve can be stored in a non-volatile memory, to avoid having to correct a fixed characteristic curve each time the system is switched on. There is also the possibility of obtaining suitably accurate characteristic curves for individual systems, e.g., to compensate for differences in flow cross sections of valves and conduits and aging of the damper.
- the invention avoids the need for a compromise which would result from an adjustment to give optimum height regulation at half load and the consequent poorer regulation at smaller and larger loads.
- the comparator 44 is programmed to adjust the characteristic curve stored in the memory zone 52.
- the measured height h is compared with the desired value h o in a further comparator 60 and the error is fed to the computer 44. If this error is over a predetermined value in the steady state, i.e. in the absence of any signals from either of the comparators 40, 42, a corresponding correcting signal is fed to the memory zone 52 to alter the characteristic curve in the sense that the error will be reduced the next time an adjusting operation takes place.
- two oppositely poled comparators 60 would be needed for making corrections in either direction as may be necessary. If a volatile memory 52 is used, the one characteristic curve can be corrected as necessary.
- An alternative would be to use a non-volatile memory in which a series of characteristic curves is stored, of which only one is used at any given time. In such case, the correcting signal from the computer 44 changes the characteristic curve in use.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Vehicle Body Suspensions (AREA)
Claims (7)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/EP1988/000295 WO1989009701A1 (en) | 1988-04-08 | 1988-04-08 | Height adjustment system for a vehicle with air suspension |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0414678A1 EP0414678A1 (de) | 1991-03-06 |
EP0414678B1 true EP0414678B1 (de) | 1992-01-15 |
Family
ID=8165259
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19880903239 Expired - Lifetime EP0414678B1 (de) | 1988-04-08 | 1988-04-08 | Höhenregelungssystem für ein fahrzeug mit luftfederung |
Country Status (5)
Country | Link |
---|---|
US (1) | US4971360A (de) |
EP (1) | EP0414678B1 (de) |
JP (1) | JP2695216B2 (de) |
DE (1) | DE3867850D1 (de) |
WO (1) | WO1989009701A1 (de) |
Families Citing this family (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5367459A (en) * | 1992-02-10 | 1994-11-22 | Trw Inc. | Apparatus for controlling dampers in a vehicle suspension system |
US5430647A (en) * | 1992-12-07 | 1995-07-04 | Ford Motor Company | Method and apparatus for maintaining vehicular ride height |
DE4333823A1 (de) * | 1993-10-04 | 1995-04-06 | Bosch Gmbh Robert | Vorrichtung zur Niveauregelung eines Fahrzeugs mit Luftfederung |
US5517847A (en) * | 1994-12-16 | 1996-05-21 | Ford Motor Company | Open compartment load leveling ride height control |
DE19853126B4 (de) * | 1998-11-18 | 2005-03-03 | Daimlerchrysler Ag | Verfahren zur Niveauregelung und Radfahrzeug mit einem Niveauregelsystem |
KR100475906B1 (ko) | 2001-10-19 | 2005-03-10 | 현대자동차주식회사 | 에어서스펜션 차량의 롤 스태빌라이저 장치 |
US8306696B2 (en) * | 2003-04-17 | 2012-11-06 | Driveright Holdings, Ltd. | Method and system for aligning a vehicle with an artificial horizon |
ES2335016T3 (es) * | 2003-04-17 | 2010-03-18 | Firestone Industrial Products Company, Llc | Procedimiento y sistema de alineacion de un vehiculo estacionario con un horizonte artificial. |
US7192012B2 (en) * | 2003-08-18 | 2007-03-20 | Haldex Brake Corporation | Air suspension system with supply air restriction valve |
US6935625B2 (en) * | 2003-08-18 | 2005-08-30 | Haldex Brake Corporation | Air suspension system with air shut off valve |
DE102004021726A1 (de) | 2004-04-30 | 2005-11-24 | Daimlerchrysler Ag | Verfahren zur Niveaueinstellung eines Fahrzeugs |
US7744099B2 (en) * | 2004-11-04 | 2010-06-29 | Driveright Holdings, Ltd. | Method and system for adjusting a vehicle aligned with an artificial horizon |
KR100784377B1 (ko) * | 2005-12-07 | 2007-12-11 | 주식회사 만도 | 선형 차고 센서를 구비한 차량의 현가장치 및 차고 제어방법 |
US8155835B2 (en) * | 2008-02-21 | 2012-04-10 | Driveright Holdings, Ltd. | Vehicle chassis height adjustment method and system |
US8191904B2 (en) * | 2009-10-02 | 2012-06-05 | Barksdale, Inc. | Hybrid leveling system |
DE102009057529A1 (de) * | 2009-12-08 | 2011-06-09 | Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr | Verfahren zur Steuerung der Niveauregulierung eines Fahrzeugaufbaus eines Kraftfahrzeuges |
US8868294B2 (en) | 2012-09-28 | 2014-10-21 | Firestone Industrial Products Company, Llc | Adjustable hysteresis circuit for control of air suspension |
US10479159B2 (en) | 2016-04-04 | 2019-11-19 | Barksdale, Inc. | Ride height leveling with selectable configurations: system and method |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0262572A2 (de) * | 1986-09-27 | 1988-04-06 | Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 | Verfahren zur Dämpferkraftverstellung von Kraftfahrzeugen |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58174007A (ja) * | 1982-04-06 | 1983-10-13 | Nissan Motor Co Ltd | 自動車高調整装置 |
JPS59191803A (ja) * | 1984-04-02 | 1984-10-31 | 株式会社荏原製作所 | 水管ボイラ |
JPS61163011A (ja) * | 1985-01-14 | 1986-07-23 | Nissan Motor Co Ltd | 電子制御ショックアブソ−バ装置 |
JPH0710643B2 (ja) * | 1985-10-22 | 1995-02-08 | トヨタ自動車株式会社 | 車輌用車高調整装置 |
JPS62214008A (ja) * | 1986-03-13 | 1987-09-19 | Komatsu Ltd | ホイ−ル式クレ−ンのサスペンシヨン制御装置 |
JPS63284011A (ja) * | 1987-05-13 | 1988-11-21 | Fuji Heavy Ind Ltd | 自動車用アクティブサスペンションの制御方法 |
-
1988
- 1988-04-08 DE DE8888903239T patent/DE3867850D1/de not_active Expired - Lifetime
- 1988-04-08 EP EP19880903239 patent/EP0414678B1/de not_active Expired - Lifetime
- 1988-04-08 US US07/411,453 patent/US4971360A/en not_active Expired - Fee Related
- 1988-04-08 WO PCT/EP1988/000295 patent/WO1989009701A1/en active IP Right Grant
- 1988-04-08 JP JP63503321A patent/JP2695216B2/ja not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0262572A2 (de) * | 1986-09-27 | 1988-04-06 | Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 | Verfahren zur Dämpferkraftverstellung von Kraftfahrzeugen |
Also Published As
Publication number | Publication date |
---|---|
JPH03503621A (ja) | 1991-08-15 |
WO1989009701A1 (en) | 1989-10-19 |
DE3867850D1 (de) | 1992-02-27 |
EP0414678A1 (de) | 1991-03-06 |
JP2695216B2 (ja) | 1997-12-24 |
US4971360A (en) | 1990-11-20 |
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